Solutions of the Force-Free Duffing-van der Pol Oscillator Equation

<table>Comparisons for <svg height="7.9499998" id="M89" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 9.2749996 7.9499998" width="9.2749996" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg> versus <svg height="11.1" id="M90" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 9.2749996 11.1" width="9.2749996" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,8.812,10.65)"><path d="M-161 571q0 -21 -15 -36t-36 -15q-20 0 -35 15.5t-15 35.5q0 21 15 36.5t35 15.5q22 0 36.5 -15t14.5 -37z" id="x307"></path></g><g transform="matrix(.017,-0,0,-.017,.062,10.838)"><path d="M515 96q-37 -44 -84.5 -76t-71.5 -32q-12 0 -18 7t-6 34t10 75l19 89h-2q-87 -113 -181 -176q-43 -29 -83 -29q-46 0 -46 63q0 31 9 67l52 222q7 36 -1 36q-10 0 -76 -50l-13 24q47 45 92 71.5t67 26.5q18 0 21 -16.5t-8 -65.5l-56 -242q-16 -67 13 -67q41 0 114 74
t114 146l32 145l74 26h11q-52 -199 -80 -347q-8 -39 6 -39q7 0 32 17.5t47 39.5z" id="x1D462"></path></g>
</svg> trajectory of the Duffing-van der pol equation (a) RK4, (b) present method.</table>

International Journal of Differential Equations

Solutions of the Force-Free Duffing-van der Pol Oscillator Equation

Figure 3